My DIY speaker project for 2 ch.

gatemplin

Just want to share some of my excitement about this project and maybe inspire someone else to build their own speakers.

I decided to build my own 2 channel speakers just over a year ago. I did a lot of research online and at the library to prepare for the project. I learned about motor topologies, enclosure design, diffraction, baffle step, crossover networks etc. I read books by Vance Dickason, David Weems and John Murphy several times. I also listened to a lot of speakers to figure out what sound I liked and try to build something similar.

I have decided to build a design that Jon Hancock is going to do using the 6.5" Extremis6 with XBL^2 from Adire Audio and the 1" German LPG 26T Titanium tweeter. It will be a small ported design tuned to 33 Hz.


In my humble opinion the crossover is THE most important part of the speaker and this one should be a beauty. It will be a 8th order cauer-elliptical filter which is based on a 4th order Linkwitz Riley. This is a very unsual and expensive design and I know of only one other design that uses this network. I will use Solen caps, resistors and air core inductors only and they will cost me a small fortune.

I am starting to build the enclosure today using 1.5" butcher block and 3/4" MDF. The ports are 2" and flared at both ends.

Here is a 10 Meg video of the Extremis pumping away. http://www.adireaudio.com/Files/Extremis6.AVI

The tweeter is used in a few high end designs like the Totem Shaman here:
http://www.totemacoustic.com/english/products/floorStanding_shaman.htm
It is also used by Aerial Acoustics.

PolkThug

Sounds like fun. Some day I'd like to make my own 2-channel speakers as well. Since you're going all out, why not use HDF instead of MDF?

gatemplin

Since you're going all out, why not use HDF instead of MDF?

I am using mostly butcher block from Ikea and the MDF should work fine for bracing. The butcher block is very stiff and strong. Here is speaker that inspired me to use the Ikea butcher block. My speakers will be painted or veneered, not raw like this.
http://members.home.nl/edgar.beers/

tryrrthg

You'd really paint or veneer over that? :eek: that cabinet is gorgeous!

Sounds like a cool project!

gatemplin

Sounds like a cool project!

Thanks!

If I could make it look that nice I would. He did a trans-laminated approach. I am just using the wood to make a box, then making figure 8 shaped braces to slide into the enclosure. I am not sure of the finish yet. I have already cut the baffles anyway. It is very likely that I will rebuild the enclosure in the summer. I have rebuilt my subwoofer twice.

dcarlson

Definitely keep us up to date. Sounds very cool.

tryrrthg

Originally posted by gatemplin
Thanks!

If I could make it look that nice I would. He did a trans-laminated approach. I am just using the wood to make a box, then making figure 8 shaped braces to slide into the enclosure. I am not sure of the finish yet. I have already cut the baffles anyway. It is very likely that I will rebuild the enclosure in the summer. I have rebuilt my subwoofer twice.

Heck I even think it looks cool unfinished. Those butcher blocks are a unique look!

dcarlson

Take a lot of pictures.

gatemplin

I'm glad that there are others here who are also interested in speaker design. My goal is to learn enough to be able to design my own crossover one day.

I built the circle jig for my router last night and tried it out, works perfect. It's set to 7" and 110mm for the woof and tweeter. The front and rear baffles are cut. Tomorrow I will plan out how much MDF I need to make the braces and the depth of the box to arrive at 21L minus the port, driver and the giant crossover.

Here is an example of a cauer-elliptic 8th order that Jon Marsh designed for another project:


I may not be able to mount the xover in the cab.

Jon is waiting on the drivers from Adire. When he finalizes the complex design I will order the tweeters and parts so it could take a while. I will definitely have pics of the finished speakers, and shots of inside the box and the drivers and crossover etc.

If anybody hasn't seen the excursion video in my first post check it out. It was made by Dan Wiggins, I love speaker ****!

VR3

That is INSANE excursion for a midbass! Jesus christ!!

Awesome design man! I wish I had the funds to do a project like that! Heck, I wish I trusted myself to building something with that kind of money! LOL!

I want to see LOTS of pics! Keep us updated!

This butcher block, how will this work?

dorokusai

Sounds like a real neat project, can't wait to see them.

audiobliss

Wow, you sure are going all out with this project, huh? Sounds like you've done a lot of research on it before you started, too. Keep us updated with lots of reports and pictures!!

And, that is an awesome mid-bass.

gatemplin

Thanks Mark and Sid. The good thing about DIY is that you can tailor the design to your own preferences. I know Mark doesn't like metal domes, but I have learned that I like them and dont find them fatiguing like others do.

That is INSANE excursion for a midbass! Jesus christ!!

Yes lots of displacement. Xmax is a linear 13mm each way, or just over 1" total. The motor has an extremely flat BL curve. It also has a copper shorting sleeve on the extended pole piece to reduce inductance and improve transient response. Adire claims that this design I am doing will have in room extension to the low 20's and flat an clean anechoic to 35 Hz!

Awesome design man! I wish I had the funds to do a project like that! Heck, I wish I trusted myself to building something with that kind of money! LOL!

It will be a lot of money, probably over $600 US and there is no resale value. I trust the design though because Jon Marsh has been designing speakers for a long time and he does more testing than some manufacturers. He is a stickler for the details.

This butcher block, how will this work?

I have deciced only to make the front and rear baffles out of butcher block. I need some of it for another project. The box will be heavily braced with MDF. I take pics of the bracing. The walls will probably be 1.5" MDF. Right now it is looking like the box will be 15+ inches deep.

Dan Wiggins at Adire said the Extremis drivers go into production Dec 7th so hopefully they will ship shortly after.

There is not much more I can do until Jon figures out the driver placement on the baffles. I will hopefully get the boxes done in the next week or two.

gatemplin

Wow, you sure are going all out with this project, huh? Sounds like you've done a lot of research on it before you started, too.

Thanks for the interest. I have done a lot of research but this is what I love to do. I have a very long way to go still and this is the start of a life long hobby for me.

The design is still considered a "budget design" by most audiophiles. I think it is the point of dimishing returns. I could use a Scan Speak, Seas Excel or Morel tweeter but I prefer metal domes and they would easily double the driver budget.

organ

Very cool. Keep us posted and show us pics of the process. It's very cool that you went for metal tweeters. A lot of people hate them but I think they sound great. They give music a little more 'edge' and 'snap'. This makes them sound exciting.

Maurice

gatemplin

Thanks Maurice.
I agree on the metal domes. There is just something about them that I like. They are very revealing and detailed and maybe a little forward. Exciting is a good way to describe them. I am talking about higher end metal domes of course.

VR3

I must say I am more of a fan to metal domes...

Tri Lam, Aluminum...

However I like Polymer domes too (atleast the ones I've heard) - personally don't like Silks

gatemplin

Just an update, I still dont have the Extremis drivers, maybe they will ship next week. After Christmas I will be modifying the LPG 26T tweeters by adding acoustic fill to the vented pole piece and removing a lens in front of the diaphragm.

I will be making a big enclosure, 34 L net tuned to 25 Hz. Jon says that it would have an output capbility from 23 Hz to 40 Hz at 1 meter, one box, anechoic, of > 100 dB, with a max power input of 50 watts. I have been playing around with this design in Unibox (still learning) and it looks like it will work well. Not too bad for a 6.5" driver.

Next up is for Jon to measure the drivers and design the crossover probably in January. I will try and get some pics of the progress this week.

gatemplin

Here is the predicted response from unibox.


[IMG]C:\Graham\Speakers\Club Polk\VB Response Extremis.gif[/IMG]

gatemplin

Here is the current plan for the box I made quickly in AutoCAD. It is big, 10" wide by 17" tall and 20" deep. It has to have the same front baffle dimensions as Jon's design to avoid adjusting the xover and it needs to be deep to accomodate the ~12" port. If I decide to use a larger diameter port later on the port will be 15" plus.

This box will be made from high quality plywood and it is a test box that I will leave unfinished until probably the summer when I will have more free time and money.

Thanks for looking!
Graham

[IMG]C:\Graham\Speakers\Club Polk\Extreme.jpg[/IMG]

gatemplin

This is the baffle layout I did in AutoCAD. The drivers are placed on the baffle to minimize the effects of baffle loading and diffraction. The result is a smoother frequency response. Jon used a program called Baffle Diffraction Simulator to design the layout.

[IMG]C:\Graham\Speakers\Club Polk\Baffle.JPG[/IMG]

gatemplin

I finished my test boxes yesterday. It may seem like a waste of time to build test boxes but I am not sure I will like the low Q sound, the 21" deep cabinets, and I am not sure the 2" flared ports are big enough. Unibox says the ports should be fine up to about 96 dB but we shall see. I dont have enough time to do a proper job now anyway, I thought the drivers would have arrived in Nov and they still aren't here. The cabinets are 3/4" ply and 1 1/4" butcher block built to the plans on the AutoCAD drawing. They were quickly painted with white latex paint.

I took this pic with a phone (I should have better pics soon ) but you can get an idea of the progress in this project. The only thing left to do on the box is to install the biwire inputs and the driver gaskets.

In the background you can see my DIY Tempest, DIY flexi TV rack, my clear pine DIY speaker stands and my Paradigms. The sides of the 'digms are red oak veneer and the front baffle is MDF with the same textured finish as the sub. I just wanted to do something unique.

Thanks for taking a look!

audiobliss

Man, those test boxes don't look bad. The DIY TV stand looks really good, too!

gatemplin

Thanks. I'll try to get a better pic of the TV stand, I broke my brothers digital camera but I snagged some pics of the tweeters before.

I have the tweeters installed in the test boxes with some Paradigm midranges and a Paradigm crossover which was also made for a 8 ohm Ti tweeter so it matches OK until I get the Extremis drivers in about a month I would guess. The tweeters sound fine but it is hard to do an evaluation without a proper xover.

The tweeters are made in Germany by LPG and they are very nice IMO. They have a thick Al face plate and the construction is very solid. They use a double magnet in the motor, they are not shielded.

gatemplin

Shot of the motor with stacked magnets.

gatemplin

Here is a pic of the speakers in the test boxes and the DIY flexi with a flexi center channel stand.

audiobliss

Man, those are some DEEP speaker boxes!!! The tweeter really look well-built.

And, the TV stand does look really great.

gatemplin

Thanks again. The speakers are deep because the front baffle has to be 10" x 17" to match Jon's crossover, the port is 12" long and to minimize the affect the reflection of the backwave has on the cone in the midrange frequencies.

I took a better pic of the TV stand and speakers.

gatemplin

Here is a better pic of the TV stand and speakers.

xsmi

Gatemplin,

Your work is superb! I was wondering, did you use the butcherblock for the top and bottom of the cabinets or for the enternal bracing?

Xavier

VR3

Is that grey fridgerator in the back... the DIY subwoofer?

If so... :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek:

Looks REALLY good man...